CAM (Crassulacean Acid Metabolism) photosynthesis in vascular plants has evolved independently numerous times from the ancestral C3 pathway to minimize water loss in response to drought stress. To minimize evapotranspiration, CAM plants close their stomata during the daytime. At night, when temperatures are lower and transpiration is relatively less, CAM plants open their stomata and fix CO2 via an enzyme called PEPC (Phosphoenolpyruvate carboxylase). The fixed carbon is stored as an organic acid in the vacuole. Stored malic acid becomes available in the daytime via decarboxylation and provides a high concentration of CO2 to the Calvin cycle. The CAM pathway largely occurs in desert plants, however, it also is found in epiphytic plants which reside in non-soil environments. Some epiphytes employ a stress-induced CAM called facultative CAM, which uses both the standard C3 pathway under normal conditions and the CAM pathway under stressed conditions. Peperomia (family Piperaceae) is an epiphytic taxon that is widespread throughout tropical regions. Pacific lineages of Peperomia have diversified into native and endemic species to the islands of Hawaii. Likely due to its epiphytic habitat, Peperomia species use CAM photosynthesis, though data is limited and only a small fraction of species have a photosynthetic pathway known. Here we aim to determine the photosynthetic pathway in native Hawaiian Peperomia. Five epiphytic, native Hawaiian Peperomia were used in this project: P. blanda, P. cookiana, P. hypoleuca, P. mauiensis, and P. sandwicensis. Plants were grown in common conditions and measured for photosynthetic traits, including gas exchange and titratable acidity, under both well-watered and drought-stressed conditions. Leaf anatomical sections were measured for cell size, air space, and overall thickness. We find a spectrum of CAM phenotypes in the species measured, from strong CAM to weak CAM and C3. One species, P. sandwicensis, had induced CAM under drought. Further work will examine gene expression differences across a gradient of C3, weak CAM, and facultative CAM species in Peperomia.